Emergency key release latch for electric locks



Oct. 28, 1958 H. L. BONE ET AL 2,85

EMERGENCY KEY RELEASE LATCH FOR ELECTRIC LOCKS Filed May 12, 1954 5Sheets-Sheet l INVENTORS Herbert L. 60129 and John W Logan J1:

7 1mm ATI'oRylzr Oct. 28, 1958 H. BONE ETAL EMERGENCY KEY RELEASE LATCHFOR ELECTRIC LOCKS Filed May 12, 1954 3 Sheet sSheet 2 l/ll/l/l/l/lnsalqtimz 5,9

Fey 2 I INVENTORS Herbert L.Bone and BY Jblzzz Wboyan J1:

MAW

THEIR ATTflHNEY Oct. 28, 1958 H. BONE ET AL EMERGENCY KEY RELEASE LATCHFOR ELECTRIC LOCKS 3 Sheets-Sheet 5 Filed May 12, 1954 fi a m 8. Q N %NWA MN O gm; mm Tm R m R m i Q N\\ mm Wm Ne 3 wum aazc QE ww R mw m NWQNQR NM mm R R mm .3 N% m v m ww Q m w NA. in 14%... \A n I w Nam NWHHHHHHJWWM QW mwm u m N w m w R R n Q6. v. v NM, Emfi N WW 5 fimww .w wQM l Q3 mm, 6 Q a m m 1 J 4 m! R g f w n Q I Mo ,WF v I J! J n 7 mm vwi. mm Sv m A m .K w n m. R L 0 1 QS N mm M Wm J F r" L \w a Q kw Il--:..... MC C H L QN EMERGENCY KEY RELEASE LATCH FOR ELECTRIC LOCKSHerbert L. Bone and John W. Logan, Jr., Forest Hills, Pa., assignors toWestinghouse Air Brake Company, Wilmerding, Pa., a corporation ofPennsylvania Application May 12, 1954, Serial No. 429,247

10 Claims. (Cl. 246-159) Our invention relates to lock devices forrailway track switches, derails, and the like, and particularly toemergency key release latches for electric locks.

In railway signaling and trafiic controlling systems, outlying trackswitches are commonly protected against operation by unauthorizedpersons by means of padlocks which may be opened by keys carried bycertain selected railway personnel. It is sometimes necessary ordesirable to supplement the protection obtained from the use of apadlock by adding another lock which may be controlled from a remotepoint or automatically in accordance with traflic conditions. A commonexpedient is to provide an outlying track switch associated with a maintrack or the center stand of a crossover connected to the operatingmechanisms of the two track switches, with an electric lock, such asillustrated for example in Letters Patent of the United States No.2,517,280, granted August 1, 1950, to Herbert L. Bone et al. Thesupplemental control imposed by an electric lock of this type permitsselected railway personnel provided with the necessary keys to initiatethe unlocking of the hand-throw lever, energization of the lock magnetof the electric lock being required before the lever latch may be movedout of the way to free the hand-throw lever.

An emergency key release is often incorporated in such electric locks toenable a trainman to unlock the electric lock without Waiting for theelectric unlock if conditions are such that he is authorized to do so.To opcrate the emergency key release of such an electric lock, atrainman must first break a seal before he can insert his key in therelease mechanism. There have been times, however, when trainmen havebroken the seal and used the emergency key release Withoutauthorization. In such cases, the fact that the emergency key releasehas been used without authorization might not be brought to theattention of the proper authorities until a signal maintainer on aperiodic inspection tour finds the broken seal on the electric lock.Considerable time may have elapsed between the unauthorized use of theemergency release and the discovery of the broken seal on the electriclock. With the seal broken, the person responsible for the unauthorizeduse cannot be ascertained nor can there be any check made as to how manytimes the electric lock was released without authority.

It i therefore an object of our invention to provide a latch for theemergency key release of electric locks which operates whenever the keyrelease is used and prevents the control contacts of the lock fromreturning to their normal or locked position.

It is a further object of our invention to provide an emergency keyrelease latch for electric locks which may bereset only by a maintainerequipped with the proper key for the electric lock housing.

Another object of our invention is to provide an emergency key releaselatch for electric locks which will permit the electric lock to bepadlocked even though the control nited States PatentO 2,858,419Patented Oct. 28, 1958 contacts of the electric lock are in theirunlocked position.

Still another object of our invention is to provide a safeguard for theemergency key release latch to maintain and insure the proper alignmentof the latch mechanism with the key release mechanism.

In carrying out the foregoing and other objects of our invention, weprovide a spring biased latching member for an electric lock similar tothat shown in the aforesaid patent. With reference to the aforementionedpatent, the foot pedal is provided with a spring biased stop sleevewhich, upon depression of the foot lever to release the hand-throwlever, is moved in the direction of the foot lever. As more fully shownand described in the aforesaid patent, the stop sleeve cooperates with alocking dog which is under the control of an electromagnet. Energizationof the electromagent will lift the locking dog out of the path of thelocking sleeve to permit the depression of the foot pedal of theelectric lock. Movable with the foot pedal is a camming nut whichcooperates with a contact operating cam so that the depression of thefoot pedal in releasing the hand-throw lever will move the cam to aposition in which the electric contacts of the lock are actuated.

The latching member of our invention is so arranged within the electriclock that a trigger arm secured to the key barrel of the emergency keyrelease will release the latching member. The end of the latching memberwill abut the locking sleeve but, as the foot pedal is depressed torelease the hand-throw lever, the end of the latching member will beinserted behind the locking sleeve, thereby preventing its return. Thefoot pedal, however, will be permitted to return to its normal positionso that the hand-throw lever may be locked in its normal or lockedposition. The holding of the locking sleeve in its forward position,however, prevents the locking dog from returning to its inoperativeposition. The retained operative position of the locking dog retains thearmature of the electromagnet in its operative condition to maintain thesignal contacts in their actuated or unlocked positions. To release thelatching member it is necessary for a maintainer provided with thenecessary key to open the case of the electric lock and reset thelatching member. The resetting of the latching member will permit thelocking sleeve to return to its unlocked position, thereby permittingthe locking dog to assume its locked position. The return of the lockingdog to its locked position will permit the armature to return to itslocked position, the actuated contacts returning to their normal orlocked position. Thus a trainman after using the emergency releasemechanism may leave the electric lock prior to the arrival of amaintainer with the certainty that no one without a key to the padlockof the lever latch can operate the foot pedal of the electric lock tofree the hand-throw lever.

Other objects and characteristic features of our invention will becomeapparent as the description proceeds.

In the accompanying figures of the drawings wherein similar referencecharacters designate similar parts in each of the several views,

Fig. 1 is a top elevational view showing the association of a lockdevice as shown in Letters Patent of the United States No. 2,517,280 toa center stand disposed between the rails of a crossover.

Fig. 2 is a top view of the electric lock with the cover removed,portions of the electric lock being broken away to show the details ofour latch mechanism.

Fig. 3 is a fragmentary end view of the key barrel andthe trigger armfor releasing the latching member upon operation of the emergency key.release, as viewed along line III-J11 of Fig. 2.

Fig. 4 is a sectional view taken approximately along the line IVIV ofFig. 2.

Fig. 5 is a sectional view taken approximately along the line V-V ofFig. 2.

Fig. 6 is a-view similar to Fig. 5 illustrating the positions of thelocking sleeve 28 and the locking dog-'30 after a latchout, and of thelocking rd-22 with the lever latch padlocked.

Fig. 7 is a sectional view taken along the line NIL-VII of Fig. 4.

Fig. 8 is a portion of Fig. 4 showing in enlarged scale the emergencykey releasemechanism, while "Fig. 9 is 'a sectional view takenapproximately along the line IX--IX of Fig. 8.

Referring now in detail of Fig. 1 of the drawings, the referencecharacter l designates a center stand having a hand-throw lever 2 foroperating a mechanical pipe connection 3 connected to manually operableswitch operating mechanisms as illustrated in the aforesaid patent.Hand-throw lever 2 is operable between two' extreme positions in whichthe pipe connections 3 will actuate the switch operating mechanisms. Anelectric lock 4 associated with hand-throw lever 2 is effective topermit operation of the stand lonly when conditions are proper for suchoperation. The electric lock 4 is controlled to permit operation of thehand-throw lever 2 only when the electromagnet of the lock is energizedby a control circuit which may be effected by an operator of acentralized traffic or remote control system, and/ or by automaticcontrol imposed by-track circuits, positions of signals, etc., asis wellunderstood in the art. As will hereinafter be more fully described, theelectric lock 4 may be released by an emergency key release. Thehandthrow lever 2 of the center stand has a normal position in which itis illustrated and may be operated-through an angular movement ofsubstantially 180 to a reverse position. The lever 2 is shown in itslocked position inthe electric lock 4 which is secured to a supportingplate 5 on ties 6.

The electric lock 4 comprises a housing 7 enclosed at its upper end by ahinged cover 8. The housing is provided with a hasp 9 while the cover isprovided with a staple 10, the bail of a padlock 11 passing through thestaple to lock the housing against unauthorized access. The housing 7 isprovided at its forward side with an integral extension 12 (Fig. 5)formed at its outer end with an upturned leg 13 and. with spacedvertical. standards 14 which, together withleg 13, form a jaw forreceiving the hand-throw lever 2 of the center stand when the lever isin its locked or normal position. The

lower portions of standards 14 support a pivot pin 15 on which ispivotally mounted a lever latch 16 movable between a padlocked position,as. illustrated in Fig. 5, through an intermediate latching position, toan unlatchedposition. In both .the padlocked and intermediate positionsof .the lever latch, the latch projects. into theupper end of the jawinsuch a manner as to prevent movementof the hand-throw lever 2 pasttthelatch. In the unlatched position, latch 16 is withdrawn from the jaw topermit movement of the hand-throwlever. In the padlocked position oflatch 16, a hasp staple 17 provided on leg 13 projects through asuitable opening 16a of latch 16, the bail 17a of apadlock, nototherwise illustrated, locking the lever latchrin its padlockedposition. Formed integrally with latch 16 are a treadle 18 and abifurcated crank arm 19, the crank arm being provided at its outer endswith slotted openings 20 which engage a pin 21 carried on the outer endof a locking rod 22. The locking rod22 is mounted for lateral slidingmovement inopenings 23a formed in a housing extension 23 in the forwardside wall of the housing 7.

The inner end of rod 22 which projects into the housing is formed ofreduced diameter to provide a shoulder 24 on the rod. The extreme innerend of the rod is threaded into a cam nut 25 slidablymounted in aslotted opening 26a provided in a boss 26 formed integrally with housing7. Sleeved collars 27 and 28 and a coil spring 29 are slipped over thereduced portion of the rod 22 before attaching the nut 25, the spring 29being disposed between the inner faces of the collars. Sleeved collar 28will hereinafter be referred to as the locking sleeve 28. When the rod22 is in its padlocked position, spring 29 is provided with suflicientinitial compression so that collar 27 is urged constantly by spring 29into engagement with shoulder 24 of the rod 22, while the locking sleeve28 is forced by the spring 29 into engagement with the end 26b of theboss 26. In this condition of the parts the spring 29 is compressed,tending to bias the rod 22 toward the right as viewed in Fig. 5. Whenthe bail 17a of the padlock is removed from the hasp staple 17, theparts'are so proportioned that the collar 27 and locking sleeve 28 willbe driven apart by the spring 29 until the collar 27 engages theadjacent end wall 23b of the housing extension 23. The rod'22 will thusbe moved to the right, as viewed in Fig. 5, to move cam nut 25 to theposition where it just touches locking sleeve 28. In this position,which is referred to asthe intermediate or unlocked position, the collar27 and locking sleeve 28 will engage the confronting surfaces ofshoulder 24 and cam nut 25, respectively. The cam nut 25 is threaded onthe rod 22 to a position so selected that, when collar 27 and lockingsleeve 28 are in engagement with the respective confronting surfaces ofshoulder 24 and nut 25, the collar 27 and locking sleeve 28 also engagethe end 23b of the housing extension 23 and the inner end 26b of theboss 26, respectively. The housing extension 23 and the boss 26constitute stops for the collar 27 and locking sleeve 28, respectively,in the intermediate or unlocked position of the rod 22.

A locking dog 30 is carried on the end of a bar 31, the other end ofwhich bar is secured to one arm of a lever 32 (Fig. 4) pivotallysupported on pivot pin 33. The pivot pin 33 is mounted in depending lugs34 provided on a supporting strap 35 secured to a magnetic bracket 36.The magnetic bracket 36 is fastened by bolts 36a to the bottom wall ofhousing 7. The other arm of the lever 32 carries an armature 37 adaptedto be attracted by an electromagnet 38 mounted in the bracket 36. In thecondition of the parts shown in Fig. 4, the magnet 38 is deenergized andthe dog 30 is disposed in the path of movement of the locking sleeve 28between the inner end of the locking sleeve and the end 3911 of a plate39 secured to the top of housing extension 23 to prevent movement of thelocking sleeve to the right, as viewed in Fig. 5. The magnet 38 whenenergized will attract the armature 37 to lift the dog 30 out of thepath of movement of locking sleeve 28 provided that a depressor 40 and ahold-down spring 40a, hereinafter more fully described, are lifted clearof the bar 31. Checking contacts, generally designated by the referencecharacter 41, for checking the position of armature 37 of theelectromagnet 38 and comprising fixed and movable contact fingers, notshown in detail, are mounted on a terminal block 42 secured to bracket36. The checking contacts 41 are operated by the armature 37 through aninsulating driving member 43 connected by a pin 43a to the bar 31 andsuitably connected to the movable contact fingers, as set forth in theaforesaid patent.

Housing 7 is provided with an opening 44 in its end adjacent to thearmature 37, and a housing member 45 is suitably secured to the housing7 in alignment with the opening 44 (Figs. 4, 8 and 9). Housing member 45contains a locking mechanism 46 which may take any -desired form. Thearrangement is such that, when a proper key is inserted into themechanism, it may be rotated to rotate an actuating member 47 driven bythe lock mechanism and projecting into the housing 7. The actuatingmember 47 has a cammed surface 48 which cooperates with a cam follower49 provided on a depending spring 50 supported from the supporting strap35.

Upon turning of the key barrel, the cammed surface 48 drives the spring50 toward the armature 37 so that an insulating pin 51 carried on thespring 50 is forced into engagement with the armature 37 and drives itto the pole pieces of the electromagnet 38. Bar 31 is thus rotated tolift the locking dog 30 out of the path of movement of the lockingsleeve 28 permitting the treadle 18 to be depressed to move the lockingrod 22 to the right, as will be described in detail hereinafter. Thehousing member 45 ofthe lock release is preferably enclosed by a hingedcover 52 biased by a spring 53 to cover the locking mechanism of therelease, eyelets 54 or the like being provided on the housing and thecover through which a sealing wire or band (not shown) is passed to sealthe lock release mechanism.

An insulating terminal block 55 (Figs. 4 and 7) fastened to the upturnedleg of a contact supporting bracket 56 secured by bolts 56a to thebottom wall of housing 7 has molded therein two rows of contactterminals 57 and 58. A movable contact finger 59 is riveted to eachterminal 57 and a fixed contact finger 60 is riveted to each terminal58, the contact fingers 59 and 60 cooperating in pairs to provide matingcontacts. Each movable contact 59 is operatively connected with aninsulating driving member 61 in a suitable manner. The member 61 isguided at its upper end for up and down movement in a slotted guide 62secured to the bracket 56, and carries near its lower end a laterallyprojecting pin 63. Block 55 and supporting bracket 56 have alignedopenings 64 through which projects an arm 65 of a pivoted operatingmember 66 (Figs. 2 and 4), the arm being bifurcated at its end andprovided with openings to receive the pin 63 of the driving member 61.

Operating member 66 comprises a substantially U- shaped member 67 (Fig.2) provided with integrally formed trunnions 68, one of which isjournaled in a bore 69'on the rear side wall of the housing 7, while theother is journaled in a trunnion screw 70 threaded through the frontside wall of the housing and secured by a nut 71. Integrally formed withthe U-shaped member 67 is the contact operating arm 65 described, and adependent arm 72 (Fig. 4). Also formed on the U-shaped mem ber is a camarm 73 having secured thereto on its under side a cam follower 74.Secured to an integral arm 75 of the U-shaped member is a depressorbracket 76. Secured to the depressor bracket 76, as by screws 76a, arethe depressor spring 40a and a laterally projecting member 77, thescrews 76a passing through the bracket 76 and threaded into suitableopenings provided in the depressor 40 disposed in axial alignment withthe arm 75.

The dependent arm 72 on the operating member 66 cooperates with a coilspring 79 confined between the arm and a boss 80 formed in the housing7. The coil spring 79 biases the operating member 66 in a clockwisedirection, as viewed in Fig. 4, about its point of pivotal support 68.In the biased clockwise position of the operating member 66, the camfollower 74 on cam arm 73 is disposed in engagement with the cam nut 25on the locking rod 22, with the cam follower 74 disposed just clear of amating beveled surface of the nut 25 (Fig. 5). The depressor spring 40ais forced firmly into engagement with the top of the bar 31 carrying thedog 30. The depressor 40 is disposed above and just clear of the bar 31,and the parts are so proportioned that the depressor spring 40a holdsdown the bar with sufficient force to overcome any tendency of the barto raise the locking dog 30 out of the path of the locking sleeve 28 as,for example, due to the energization of magnet 38,'or in response tovibrational disturbances of the mech anism such as would be occasionedby passing trains, etc. The;driving member 61 is positioned by the arm65 of the operating member 66 so that the contacts carried by block 55assume the positions in which they are shown in Fig. 7. I

The electric lock is further provided with an indicator designatedgenerally by the reference character 81 (Fig.

5). The indicator may be viewed through a window 82 provided in thecover 8 of the housing. As more particularly set forth in the aforesaidpatent, the indicator 81 is actuated by the extending member 77 securedto the depressor bracket 76 of the lock.

The electric lock and center stand hereinbefore described operate in amanner similar to that described in Letters Patent of the United StatesNo. 2,517,280. As more fully described in the aforesaid patent, theremoval of the padlock bail 17a from the hasp staple 17 will permit thecoil spring 29 to move the locking sleeve 28 to the right to itsafore-described intermediate position, the cam nut 25 lifting the camfollower 74 and cam arm 73. Operating member 66 is thus rotated in acounterclockwise direction to lift the depressor 40 and depressor spring40a to permit arm 31 to be raised upon energization of the electromagnet38. Upon energization of the electromagnet 38 of the lock, the treadle18 may then be depressed to move the locking rod 22 to its unlockedposition, the locking dog 30 having been lifted so that the lockingsleeve 28 may be moved to the right. In moving to its intermediateposition, the locking rod will carry the cam nut 25 with it so that thecamming surface on the cam nut engages the cammiug surface of the camfollower to lift the cam arm 73 of the operating member 66. Theoperating member 66 will thus be rotated in a counterclockwise direction(Fig. 4) to move the driving member 61 secured to the arm 65 in adownward direction, thereby actuating the contacts 59--6tl. Theenergization of the electromagnet 38 in rotating the arm 32 to lift thelocking dog 30 moves the driving member 43 in an upward direction toactuate the checking contacts 41 secured to the terminal block 42. Theactuation of the contacts 59-60 by the driving member 61 sets up thenecessary circuits for thesafe operation of the center stand. Thedepression of the foot pedal 18 will remove the lever latch 16 so thatthe hand-throw lever 2 may be thrown to its reverse position. A returnof the hand-throw lever to its normal position and the return of thelever latch 16 to its latching position will restore the electric lockelements to their intermediate positions. The lifting of the foot pedal18 and the insertion of padlock bail 17a in the hasp staple 17 willrestore the lock to its locked position as shown in Fig. 5.

As more fully described in the aforesaid patent, the use of theemergency release lock mechanism 46 will rotate the actuating member 47so that the cammed surface 48 will move the cam follower 49 to the left,as viewed in Fig. 8, to move the spring 50 and its attendant pin 51against the armature of the electromagnet 38. The clockwise rotation ofthe armature 37 about the pin 33 will move the arm 31 upwardly to liftthe locking dog 30 to permit the movement of the locking sleeve 28 inthe manner herein described.

In order to operate the emergency release lock mechanism, it isnecessary for the trainman to cut the lock wire or band used in sealingthe lock mechanism cover 52. Although the use of the emergency releaselock mechanism in the initial case may have been authorized, the.sealing wire or band passing through the eyelets 54 of the cover andcase of the emergency release lock mechanism will remain severed and anyfuture use of the emergency release lock will not be detected. While anauthorized use of the electric lock as described is brought to theattention of the maintenance department and a maintainer sent 'to resealthe electric lock, any unauthorized use of the electric lock may not bebrought to the attention of the proper authorities for some time, oruntil a signal maintainer on a periodic inspection tour notices thebroken seal on the lock. Since only the maintainer has access to theinside of the lock housing, a latching mechanism is now provided for theelectric lock for preventing the resetting or clearing of the signals 7:set .by the actuated contacts of the electric lock,. thelatching-mechanismpartsbeing; inaccessible from. the exterior of thehousing.

To this end, therefore, thereeissecured to the interior of the housing 7(Figs 2 and 3), a latch guide bracket 83 formed with two parallelarms.83a ands3b, the arm 83b. being the longer of the two. At the junction ofthe short arm 83a with the bracket 83 an elongated opening 830 isprovided; The longer arm 83b of the latch guide bracket is also providedwith an elongated opening 83d. adjacent'to the end of the arm. Securedto the extreme end of the longer arm 83b of the latch guide. bracket .isa spring stud 84. Slidably received in theopenings 83c and.83d providedin the latch guide bracket. arms is, a latch bar 85, the latch bar beingof an open 8. form. The end of the latch bar 85 cooperating with theshorter arm 83a of the guide bracket is providedwith. an elongated.notch 85a, while the other end of .the latch bar cooperating with thelonger arm 83b of the guide bracket is formed with a reduced end 85bwhich passes through the opening 83d of the bracket. Secured to thelatch bar'adjacent to the notch 85a is a spring; stud 86.Interconnecting the spring studs 84 and 86 is a coil spring 87, whichtends to move the latchbar to the left, as viewed in Fig. 2. It will benoted that the right-hand edge of the notch 85a abuts the arm 831 1.ofthe latch guide bracket so that the latch 'bar is prevented from beingmoved toward the left by the coil spring 87.

To release the latch bar from the guide bracket, a trigger arm 88 issecured to the actuating member 47 of the locking mechanism 46 (Fig. 3).In rotating the actuating'member by the emergency key, the trigger arm88 will be moved clockwise to abut the end of the latch bar 85 torelease the latch bar notch from the guide bracket arm 83a. The coilspring 87 may now move the latch bar toward the left, the end 85b of thelatch bar abutting the locking sleeve 28. It will be noted that thelatch bar is tripped before the emergency key has rotated far enough tooperate the lock armature. The latch bar will thus be tripped before thelever latch 16 is freed. After the latch bar has been tripped and thelocking dog 30 lifted in the manner hereinbefore described, thedepression of the foot pedal 18 will move the locking sleeve 28. towardthe right as seen in Fig. 5. The movement of the locking sleeve willpermit the spring 87 to move the latch bar end portion 85b behind thelocking sleeve 28.so that the latch bar is now between thelocking sleeveand the end 2612 ofthe boss 26 as illustratedin Fig. 6. The lever latchwill be operated in its normal manner to release the hand-throw lever 2.

The tripping of the latch bar upon use of the emergency key release willnot prevent the padlocking of the electric lock: in the normal manner.However, since the latch bar is behind the locking sleeve 28, thelocking sleeve will be prevented from returning to its normal position.The locking dog 30 will therefore be prevented from returning to itsnormal locked position (Fig. 6) so that the arm 31 is now kept in itsextreme or energized position. The armature operated checking contacts41 will thus be actuatedby the lifted arm 31 and lifted driving member34 pivoted to the arm. The arm 31 being held up will hold up the arms 73(Fig. 6) and 75 of the operating member 66 due to the abutment of thearm 31 with the depressor 40. The operating member 66 will thus be heldin its counterclockwise or actuated position to maintain the contacts59-60 actuated. Since the cover 8 of the housing 7 is locked by thepadlock 11 to which only the maintainer has a key, it will be apparentthat, Whether the use of the emergency lock be authorized orunauthorized, .the signals or circuits controlled over the contacts59-60 provide a tell-talethat the emergency key release mechanism hasbeen used.

To reset the signals or circuits actuated by the contacts 59 -60, themaintainer must'unlock the padlock 11 and remove the cover 8. By pushingthe latch bar .to the right (Fig. 2), the tension of the coil spring 87will cause the notch 85a of the latch bar to catch on the arm'83a of thelatch guide bracket. It will be necessary before, the latch bar isreleased to step on the foot pedal 18 to release the pinching action ofthe lockingsleeve 28-to permit the withdrawal of the latch bar frombehind the sleeve.

It will be noted that the right-hand end of the. latch. bar 85 isnotched as at 850 to provide enough clearance to return the trigger armto its normal positionaftertripping of the latch bar even though theleft-hand end of the latch bar is still held against the locking. sleeve'28. As previously described, this condition exists until the trainmansteps on the foot treadle. This feature .enables the. trainman to removehis key even though he may, for some reason, decide not to press thefoot treadle'afterhehas used the emergency release. bar will be releasedthe next time the foot treadle is-operated whether the locking dog iswithdrawn by electrically 1 energizing the electromagnet or turning thekey release.

In checking the electric lock4 hereinbefore described. during a regulartour of inspection, the maintainer may;

in the course of his work, accidentally trip the latchwbar- 85. Thelatch bar may easily be reset in the manner here-- in described.However, should the latch bar be tripped by the inadvertent rotation ofthe trigger arm 88- ina clockwise direction (Fig. 3) and the latch barreset with the trigger arm beyond the latch bar as indicated inthedashed position of the arm in Fig. 3, it may prove diffi cult orimpossible to insert a key in the emergency release mechanism due to therotation of the locking mechanism 47 by the trigger arm.

To avoid this difficulty there is riveted to the-inside of the cover aprotruding member 90 which, when the: cover is closed, extends into thehousing 45 (Fig. 8). Se-

cured to the inwardly projecting surface of member 90-'is an extendingridge or ward 91 which is adapted to register in the space between thekey cams 92 and 93 as indicated" in the dashed position in Fig. 9,provided on the locking mechanism 46, the ward 91 passing throughan'appropri ate keyhole plate 94 secured within the housing 45. The ward 91will only register properly within the'space='be'-- tween the cams 92and 93 'when the trigger arm 88 is in In any other position, the ward'91" will abut the outer surface of cam 93 to prevent the'closing andsealing of the cover 52'. Withthe cover SZ'Cprovided with a projectingridge or-ward as 'described'and"'- the cover closed,the trigger arm willbe held in-its' locked Should the cover 52'be open andthe-trigger itslocked position.

position. arm rotated, the cover cannot be closed and sealed until thetrigger arm is restored toits proper position. i

The latchout mechanism as herein described may be used advantageously onvarious forms of electric'locks. With a latchout mechanism of thecharacter described; the authorized or unauthorized use of the emergencyk'ey release of the electric lock will provide'a tell-tale either by wayof setting a restrictive signal for traffic 'moving over the protectedswitch, or by other changes in the particular control circuits used,which may only be reset to normal by a maintainer equipped with theproper pad lock key. Delays in moving traffic over such a protectedswitch are also reduced to a minimum in that the electric lock latchmechanism may be padlocked in its locked position after the hand-throwlever has been restoredft'oits normal position by a trainman withoutwaiting'for the" arrival of the maintainer to reset the latchoutmechanism; I The additional safeguard provided by the ridge or on theemergency release cover is also advantageous 'iir that proper relationof the latchout mechanism Withthe' emergency key release is at all timesmaintained and as A sured.

key release for an electric lock embodying our invention,

In this case, the latch 9 it is understood that various changes andmodifications may be made therein within the scope of the appendedclaims without departing from thespirit and scope of our invention.

Having thus described our invention, what we claim is:

1. A latchout mechanism for a member movable from a locked position toan unlocked position, said member being prevented from being moved toits unlocked position by a locking dog positioned in its path,comprising, release means for moving the locking dog out of the path ofthe movable member, a latch member movable behind said movable member inits unlocked position to prevent the return of said movable member toits locked position, and means operatively connected to said releasemeans for tripping said latch member upon operation of said releasemeans to permit movement of the latch member behind said movable member.

2. A latchout mechanism for a member movable from a locked position toan unlocked position, said member being prevented from beingmoved to itsunlocked position by a locking dog positioned in its path, comprising,release means for moving the locking dog out of the path of the movablemember, a latch member biased for movement into the path of movement ofsaid movable member, means for holding said latch member out of the pathof said movable member, and means operatively connected to said releasemeans for tripping said latch member upon operation of said releasemeans, said latch member when tripped abutting said movable member inits locked position, the movement of the movable member to its unlockedposition after the locking dog is moved out of its path by the releasemeans permitting the latch member to be moved behind said movable memberto prevent the return thereof to its locked position.

3. A latchout mechanism for a member movable from a locked position toan unlocked position, said member being prevented from being moved toits unlocked position by a locking dog positioned in its path,comprising, release means movable from an inoperative position to anoperative position for moving the locking dog out of the path of themovable member when the release means is moved to its operativeposition, a latch member movable behind said movable member in itsunlocked position to prevent the return of said movable member to itslocked position, means operatively connected with said release means fortripping said latch member upon initiating the movement of the releasemeans from its inoperative to its operative position to permit movementof the latch member behind the movable member, and a locking elementmovable into and out of engagement with said release means, said lockingelement being movable into engagement with said release means only whensaid release means and tripping means are in their inoperativepositions, said locking element when in engagement With said releasemeans preventing movement of the release means and tripping means totheir operative positions.

4. A latchout mechanism for a member movable from a locked position toan unlocked position, said member being prevented from being moved toits unlocked position by a locking dog positioned in its path,comprising, release means movable between an inoperative and operativeposition for moving the locking dog out of the path of the movablemember when said release means ismoved to its operative position, alatch member biased for movement into the path of movement of themovable member, means for holding said latch member out of the path ofsaid movable member, means operatively connected to said release meansfor trippinpg said latch member upon initiating the movement of saidrelease means to its operative position, said latch member when trippedabutting the movable member in its locked position, the movement of themovable member to its unlocked position upon withdrawal of the lockingdog by the release means from me path of movement of the movable memberpermitting 10 the latch member to be moved behind the movable member toprevent the return thereof to its locked position, and a locking elementmovable into and out of engagement with said release means, said lockingelement being movable into engagement with said release means only whensaid release means and connected tripping means are in their inoperativepositions, said element when in engagement with said release meanspreventing the movement of said release means and tripping means totheir operative positions.

5. A latchout mechanism for a member movable from a locked position toan unlocked position, said member being prevented from being moved toits unlocked position by a locking dog positioned in its path,comprising, release means for moving the locking dog out of the path ofthe movable member, a latch member movable behind said movable member inits unlocked position to prevent the return of said movable member toits locked position,

means operatively connected to said release means for tripping saidlatch member upon operation of said release means to permit movement ofthe latch member behind said movable member, and control elementsactuated by said movable member in moving from its locked position toits unlocked position, said control elements remaining actuated as longas said movable member is in its unlocked position.

6. A latchout mechanism for a member movable from a locked position toan unlocked position, said member being prevented from being moved toits unlocked position by a locking dog positioned in its path,comprising, release means for moving the locking dog out of the path ofthe movable member, a latch member biased for movement into the path ofmovement of said movable member, means for holding said latch member outof the path of said movable member, means operatively connected to saidrelease means for tripping said latch member upon operation of saidrelease means, said latch member when tripped abutting said movablemember in its locked position, the movement of the movable member to itsunlocked position after the locking dog is moved out of its path by therelease means permitting the latch member to be moved behind saidmovable member to prevent the return thereof to its locked position, andcontrol elements actuated by said movable member in moving from itslocked position to its unlocked position, said control elementsremaining actuated as long as said movable member is in its unlockedposition.

7. A latchout mechanism for a member movable from a locked position toan unlocked position, said member being prevented from being moved toits unlocked position by a locking dog positioned in its path,comprising, release means movable between an inoperative and operativeposition for moving the locking dog out of the path of the movablemember when said release means is moved to its operative position, alatch member biased for movement into the path of movement of themovable member, means for holding said latch ember out of the path ofsaid movable member, means operatively connected to said release meansfor tripping said latch member upon initiating the movement of saidrelease means to its operative position, said latch member when trippedabutting the movable member in its locked position, the movement of themovable member to its unlocked position upon withdrawal of the lockingdog by the release means from the path of movement of the movable memberpermitting the latch member to be moved behind the movable member toprevent the return thereof to its locked position, control elementsactuated by said movable member in moving from its locked positiontorits unlocked position, said control elements remaining actuated aslong as said movable member is in its unlocked position, and a lockingelement movable into and out of engagement with said release means, saidlocking element being movable into engagement with said release meansonly when said release means and connected tripping means are in theirinoperative positions, said element when in. engagement with saidrelease means preventing the movement of said release means and trippingmeans to their operative positions.

8. In. combination with a throw lever operatively connected with aswitch operating mechanism and operable between two extreme positions inone of which positions said lever is locked to prevent operation of theswitch operating mechanism, a lock device having a latch member forlocking said lever and movable from an intermediatelatched position toan extreme latched position and'an extreme unlatched position, means forlocking said latch member in its extreme latched position, a membermovable from an intermediate position to extreme'locking andlunlockingtpositions, means resiliently interconnecting said movablemember and said latch member and permitting relative movement betweensaid members, said means biasing said movable-member and said latchmember to their intermediate positionslwhen said locking means isunlocked, electrical control elements actuated when said-movable memberis in its intermediate and unlocked positions, a locking dog inthe pathof the movable member to prevent movement of said movable and latchmembers from their intermediate positions to their respective unlockedand unlatched positions, key operated 'means for moving said locking dogout of the path of said movable-member, a latching bar biased formovement into the path-of said'movable member, and means forming a partof said key operated'means fortripping said latching bar uponinitiatingthe operation ofsaid key operated means, said latching barafter tripping being biased against said movable member in its lockedand intermediate positions, the movement of said movable member to itsunlocked position by the latch member permitting the latching bar tomove into the path behind the movable member'to hold the movable memberagainst return to its intermediate and locked positions, the resilientinterconnecting means permitting the return of the latch member to itslatching position to lock the throw lever against movement, the actuatedelectrical control elements providing a tell-tale that the key operatedmeans was operated.

9.' In combination with'a throw lever operatively connected with aswitch operating mechanism and operable between two extreme positions inone of which positions said lever is locked to prevent operation of theswitch operating mechanism, a lock device having a latch member forlocking said lever and movable from an intermediate latched position toan extreme latched position and an extreme unlatched position, means forlocking said latch member in its extreme latched position, a membermovable from an intermediate position to extreme locking and unlockingpositions, means resiliently interconnecting said movable member andsaid latch member and permitting relative movement between said member,said means biasing said movable member and said latch member to theirintermediate positions when said locking means is unlocked, a lockingdog in the path of the movable member to prevent movement of saidmovable and latch members from their intermediate positions to theirrespective unlocked and unlatched positions, electrically operated meansfor moving said locking dog out of the path of said movable member, keyoperated means for moving said locking dog out of the path of saidmovable member, a latching bar biased for movement into the path ofsaidmo-vable member, and means forming a part of said -key operatedmeans for tripping said latching bar upon initiating the operation ofsaid key operated means, said latching bar after tripping being biasedagainst said movable member in its locked and intermediate positions,-the movement of said movable member to its unlocked'position by thelatch member permitting the latching barto move into the path behind themovable memberto hold the movable member against return to itsintermediate and locked positions, the resilient interconnecting meanspermitting the return of the latch member to'its latching position tolock the throw lever against movement.

10. In combination with a throw lever operatively connected withavswitch operating mechanism and operable between two extreme positionsin one of which positions said lever is locked to prevent operation ofthe switch operating mechanism, a lock device having a latch member forlocking said lever and movable from an intermediate latched position toan extreme latched position and anextreme unlatched position, means forlocking said latch member in its extreme latched position, a membermovable from an intermediate position to extreme locking and unlockingpositions, means resiliently interconnecting said movable member andsaid latch member. and permittingrelative movement between said member,said means biasing said movable member and said latch member to theirintermediate positions when said locking means is unlocked, electricalcontrol elements actuated when said movable member is in itsintermediate and unlocked positions, a locking dog in the path of themovable member to prevent movement of said movable and latch membersfrom their intermediate positions to their. respective unlocked andunlatched positions, electrically operated means for moving said lockingdog out of the pathof said movable member, key operated means for movingsaid locking dog out of the path of said 'movable member, a latching barbiased for movement into the path of said movable member, and meansforming a part of said'key operated means for tripping said. latchingbar upon initiating the operation of said key operated means, saidlatching bar after tripping being biased against-said movable member inits locked and intermediate positions, the movement of said movablemember to its unlocked vposition by the latch member permitting thelatching bar to move into the path behind the movable member to hold themovable member against returntto its intermediate and locked positions,the resilient interconnecting means permitting the return of thelatch'member to its latching position to lock the throw lever'againstmovement, the actuated electrical control elements providing a tell-talethat the key operated means wasoperated.

References Cited in the file of this patent UNITED STATES PATENTSLangdon Aug. 28, 1951

